Recent trends in prenatal genetic screening and testing

Abstract

Prenatal testing in recent years has been moving toward non-invasive methods to determine the fetal risk for genetic disorders without incurring the risk of miscarriage. Rapid progress of modern high-throughput molecular technologies along with the discovery of cell-free fetal DNA in maternal plasma led to novel screening methods for fetal chromosomal aneuploidies. Such tests are referred to as non-invasive prenatal tests (NIPTs), non-invasive prenatal screening, or prenatal cell-free DNA screening. Owing to many advantages, the adoption of NIPT in routine clinical practice was very rapid and global. As an example, NIPT has recently become a standard screening procedure for all pregnant women in the Netherlands. On the other hand, invasive sampling procedures remain important, especially for their diagnostic value in the confirmation of NIPT-positive findings and the detection of Mendelian disorders. In this review, we focus on current trends in the field of NIPT and discuss their benefits, drawbacks, and consequences in regard to routine diagnostics.

Keywords: NIPT; amniocentesis; cffDNA; fetal aneuploidies; non-invasive; screening.

Figure 1.. Principle of non-invasive prenatal testing.

Maternal blood consists of maternal and placental cells, which release their DNA content directly into maternal circulation. Therefore, cell-free fetal elements (for example, DNA, RNA, and proteins) are present in the blood of pregnant woman and can be used as biomarkers for prenatal testing and diagnosis ^, .

Figure 2.. Scheme of silicon-based nanostructured microfluidic platform (Cell Reveal™).

The microfluidic device is coated with antibodies which can bind the corresponding antigens on the surface of circulating fetal nucleated red blood cells (RBCs). By this method, fetal cells can be separated from other components of whole maternal blood.